The one we currently have works because we are guaranteed to be in both bowls over a 2 year period. BYU loses it's negotiating power when it can't guarantee the bowl it's negotiating with that it will play there at some point. I don't think BYU will be able to negotiate this sort of deal on their own.
Where this could work is if BYU could convince a conference to include them in their bowl pool. BYU would likely have to pay into the conference bowl payout pot and take an equal share. This is the only way I see a tiered bowl plan working out for BYU, and I don't think it's very likely.
The conferences have all the power when it comes to bowl negotiation. I could be wrong though. Help me with my unbelief.